Polyamide compositions having a high modulus and a low dielectric constant and use thereof

Abstract

The use of a mixture of solid and hollow glass reinforcements with an alloy of at least one polyamide and at least one polyolefin, the mixture of solid and hollow glass reinforcements including from 5 to 50% by weight of hollow glass beads relative to the total of solid and hollow glass reinforcements for the dry preparation at 23° C. of a composition having a modulus at least equal to 8 GPa and a dielectric constant Dk less than or equal to 3.5 as measured according to ASTM D-2520-13, at a frequency of at least 1 GHz, at 23° C., under 50% RH.

1 . A method of using a mixture of solid and hollow glass reinforcements with an alloy consisting of at least one polyamide and at least one polyolefin, said mixture of solid and hollow glass reinforcements comprising from 5 to 50% by weight of hollow glass beads relative to the total of solid and hollow glass reinforcements,
 excluding polyamide 6 and 66,   for the dry preparation, at 23° C., of a composition having a modulus at least equal to 8 GPa, and a dielectric constant Dk, less than or equal to 3.5, as measured according to ASTM D-2520-13, at a frequency of at least 1 GHz, at 23° C., under 50% RH.   
     
     
         2 . The method according to  claim 1 , wherein the dielectric loss (tan delta) of said composition is less than or equal to 0.01, as measured on a dry sample, at 23° C., under 50% RH, at a frequency of at least 1 GHz, according to ASTM D-2520-13. 
     
     
         3 . The method according to  claim 1  or  2 , wherein said mixture of solid and hollow glass reinforcements, in addition to hollow glass beads, comprises solid glass fibers selected from circular cross-section glass fibers, flat cross-section glass fibers and a mixture thereof. 
     
     
         4 . The method according to  claim 3 , wherein said mixture of glass reinforcements consists of 50 to 95% by weight of solid glass fibers and 5 to 50% by weight of hollow glass beads. 
     
     
         5 . The method according to  claim 1  wherein said alloy consists of at least one polyamide and at least one polyolefin, the polyamide/polyolefin weight ratio of which is between 95/5 and 50/50. 
     
     
         6 . The method according to  claim 1  wherein said at least one polyolefin is selected from grafted polyolefins and non-grafted polyolefins and a mixture thereof. 
     
     
         7 . The method according to  claim 6 , wherein the reactive units of the grafted polyolefin are chosen from esters of unsaturated carboxylic acids. 
     
     
         8 . The method according to  claim 6 , wherein the grafted polyolefin is propylene-based. 
     
     
         9 . The method according to  claim 6 , wherein the ungrafted polyolefin is selected from ethylene, propylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicocene, 1-dococene, 1-tetracocene, 1-hexacocene, 1-octacocene and 1-triacontene. 
     
     
         10 . The method according to  claim 6  wherein the ungrafted polyolefin is propylene-based. 
     
     
         11 . The method according to  claim 5 , wherein said alloy consists of at least one polyamide and a mixture of a polypropylene-based grafted polyolefin and a polypropylene-based non-grafted polyolefin. 
     
     
         12 . The method according to  claim 1 , wherein said at least one polyamide is selected from semi-crystalline polyamides, amorphous polyamides and a mixture thereof. 
     
     
         13 . The method according to  claim 1 , wherein said alloy consists of a single polyamide which is an amorphous polyamide and at least one polyolefin. 
     
     
         14 . The method according to  claim 13  wherein said amorphous polyamide is a polyamide of formula A/XY, wherein:
 A is an aliphatic repeating unit obtained by polycondensation: 
 of at least one C6 to C18 amino acid, or 
 of at least one C6 to C18 
 of at least one C4-C36 aliphatic diamine Ca, with at least one C4-C36 dicarboxylic acid Cb; 
 XY is an aliphatic repeating unit obtained by polycondensation: 
 of at least one cycloaliphatic diamine, or of at least one linear or branched aliphatic diamine X and of at least one aromatic dicarboxylic acid or of at least one aliphatic dicarboxylic acid Y. 
 
     
     
         15 . The method according to  claim 13 , wherein said amorphous polyamide is selected from 11/B10, 12/B10, 11/BI/BT, 11/BI. 
     
     
         16 . The method according to  claim 1  wherein said alloy consists of a single semi-crystalline polyamide or a mixture of two semi-crystalline polyamides and at least one polyolefin. 
     
     
         17 . The method according to  claim 16 , wherein the semicrystalline polyamide is chosen from aliphatic polyamides. 
     
     
         18 . The method according to  claim 16 , wherein said polyamide mixture is a mixture of an aliphatic polyamide. 
     
     
         19 . The method according to  claim 17 , wherein the aliphatic polyamide is chosen from PA610, PA612, PA1010, PA1012, PA1212, PA11 and PA 12. 
     
     
         20 . The method according to  claim 17 , wherein the aryl-aliphatic polyamide is selected from MXD6, MXD10, MXD12. 
     
     
         21 . The method according to  claim 17 , wherein the semi-aromatic polyamide is chosen from PA11/9T, PA11/10T, PA 11/12T, PA12/9T, PA12/10T, PA12/12T. 
     
     
         22 . The method according to  claim 11 , wherein said alloy consists of a single polyamide which is an amorphous polyamide, and of a mixture of a polypropylene-based grafted polyolefin and a polypropylene-based non-grafted polyolefin. 
     
     
         23 . The method according to  claim 11 , wherein said alloy consists of a mixture of two semi-crystalline polyamides and of a mixture of a polypropylene-based grafted polyolefin and a polypropylene-based non-grafted polyolefin. 
     
     
         24 . The method according to  claim 1 , wherein the composition comprises additives. 
     
     
         25 . The method according to  claim 1 , wherein the composition comprises at least one prepolymer. 
     
     
         26 . A composition comprising:
 30 to 70% by weight of an alloy consisting of at least one polyamide and at least one polyolefin, the polyamide/polyolefin ratio being from 95/5 to 50/50;   30 to 70% by weight of a mixture of solid and hollow glass reinforcement; excluding polyamide 6 and 66, and   0 to 11% by weight of at least one prepolymer;   0 to 5% by weight of fillers, and   0 to 2% by weight,   the sum of the proportions of each constituent of said composition being equal to 100%.   
     
     
         27 . The use of A method of using a composition prepared according to the method of  claim 1 , for the manufacture of an article. 
     
     
         28 . The method according to  claim 27 , wherein the article is manufactured by injection molding. 
     
     
         29 . An article obtained by injection molding with a composition prepared according to the method of  claim 1 .